The invention relates to power transmission belt installation tools and more particularly to belt installation tools having a plurality of flexibly connected segments for engaging a pulley and each segment having a belt bearing surface whereby a flexible belt is progressively guided onto a pulley or idler.
Belt drive systems comprise a significant and widely used form of mechanical power transmission. Generally a belt runs between two or more pulleys or idlers, more particularly a driver and driven pulley and/or an idler or idlers.
In order to efficiently transmit power between the driver and driven pulleys the belt is installed with a predetermined preload or tension. The amount of tension is generally a function of the horsepower and torque requirements of the drive. Increased horsepower or torque requirements will generally require a commensurate increase in the belt tension.
In order to achieve the proper tension, one or more of the pulleys is loosened so the shaft or shafts can be moved to allow a slack condition in the belt. Then, the belt is looped over the pulleys. The loosened pulley or pulleys are then pulled or tightened into a predetermined position, resulting in a tension being created in the belt. This process requires the pulley(s) to be mechanically adjusted in order to properly preload the belt.
Belts may be installed on pulley systems using other methods. For systems with an automatic tensioning device or tensioner, the tensioner is set, the belt is placed over the tensioner, and the tensioner is then released to move to its operational location, thereby tensioning the belt.
For belt systems without a tensioner, a belt is wrapped around the pulley(s) and then a pulley is tightened in its final location by a bracket, bolt or similar device.
Another method of installing a belt involves use of a tool that presses the belt into a pulley groove without mechanically adjusting the pulleys. The tool is used adjacent to a pulley. As the pulley is turned the tool stretches the belt while laterally forcing it into a pulley groove.
Representative of the prior art is European Patent No. 0 831 247 B1 to Hutchinson which discloses a tool having a radial thrust area resting against a girth of the pulley, keeping a belt away from a pulley until it reaches a plane spaced from a pulley surface. The belt is then forced into the pulley groove.
Also representative of the art is U.S. Pat. No. 4,193,310 (1980) to Boyer et al. which discloses a pulley having a diverging means extending radially and laterally from the rim for engaging and seating the belt on the pulley rim. This invention does not comprise a bearing surface for gradually entraining a belt on a pulley, instead having a peg that abruptly bends the belt into the pulley groove.
The prior art device forces a belt to bend over small radius portions of the tool, causing high stress concentrations that damage the belt during installation. Further, as the belt is forced into the groove, high lateral loads damage the sidewalls of the belt. Finally, the transverse motion of the belt as it moves into the pulley groove may damage the belt ribs.
What is needed is a belt installation tool having a plurality of segments engaging a pulley rim. What is needed is a belt installation tool having flexibly connected segments. What is needed is a belt installation tool having segments together comprising an arcuate belt bearing surface. What is needed is a belt installation tool having a plurality of segments each having a surface substantially normal to the belt bearing surface for urging a belt into a pulley groove. The present invention meets these needs.
The primary aspect of the invention is to provide a belt installation tool having a plurality of segments engaging a pulley rim.
Another aspect of the invention is to provide a belt installation tool having flexibly connected segments.
Another aspect of the invention is to provide a belt installation tool having segments together comprising an arcuate belt bearing surface.
Another aspect of the invention is to provide belt installation tool having a plurality of segments each having a surface substantially normal to the belt bearing surface for urging a belt into a pulley groove.
Other aspects of the invention will be pointed out or made obvious by the following description of the invention and the accompanying drawings.
The invention comprises a belt installation tool for installing a flexible belt on a pulley. The tool comprises a plurality of segments. Each segment comprises a substantially flat belt bearing surface and a lip for engaging a pulley rim. A flexible connector connects the segments with a headpiece flexibly attached to one end of the string of segments. Each adjacent belt bearing surface when assembled together form a substantially arcuate surface having a radius substantially similar to the radius of a pulley. The tool engages a pulley rim, conforming to the curve of the pulley rim. The belt bearing surface describes a tapered belt bearing surface. A surface normal to the belt bearing surface on each segment urges a belt from the tool onto a pulley as the pulley is turned.